This invention relates to traversely interlocking structural members which form a grid system.
Grid systems for supporting a plurality of individual panel members in the same plane are well known. Such systems are used for example, for suspended ceilings in many types of buildings. Such grid systems are described in U.S. Pat. Nos. 3,350,125; 3,378,976; 3,590,544; 3,675,957; 3,748,998; 3,782,055; 4,019,300; and 4,157,000.
In one type of installation, the grid system comprises a support member and a pair of opposing transverse members intersecting with and abutting against the support member. In addition, the support members can be intersected by a single transverse member such as proximate to a lighting fixture. The support members and transverse members have a similar configuration, each comprising a vertical web and a lower support channel. The support channel comprises a downward facing groove of a first color and a downward facing flat on either side of the groove. The flat is of a second color that contracts with the first color.
With this configuration, there can be an appearance problem. Namely, at the intersection of the support members with the transverse members, the color of the downward facing groove of the transverse members is not continuous, the grooves of opposing transverse members being spaced apart by the flats of the support member.
One solution to this appearance problem is to place a notch on the support member at the locations at which it is contacted by opposing transverse members. However, there are serious problems with using a notch. For example, it substantially reduces the load carrying capacity of the support member. Further, forming a notch in the support member greatly decreases the rate at which the support member can be manufactured, thereby resulting in a substantial increase in the cost of production for the support member.
Another disadvantage of using a notch is that there is no flexibility in locating lighting fixtures and the like in the ceiling grid structure. The preformed notch results in preordained location of lighting fixtures and the like. With grid systems where the support member is not notched, the transverse member can intersect the support member whenever the vertical web of the support member has a slot.
In view of these problems, it is apparent that there is need for a ceiling grid structure which retains the attractive appearance of the contrasting colors of the groove and the flats, but which also dispenses with notched support members and the disadvantages associated therewith, and which allow transverse members to intersect a support member wherever a prepunched slot is located.